In the United States (US), gay, bisexual and other men who have sex with other men (MSM) continue to be disproportionately affected by HIV accounting for 61% of new cases in 2010. Young African American or Black MSM were the only group in the US with a statistically significant increase (48%) in new HIV infections between 2006 and 2009. In New York City (NYC) in 2011, 51% of new HIV diagnoses were among MSM, and new diagnoses among young MSM (<30) increased from 2001 to 2010. In NYC, young Black MSM accounted for approximately 50% of new HIV diagnoses among young, MSM in 2011. The disproportionate prevalence among young African American MSM is not explained by sexual risk behavior or drug and alcohol use, although sociostructural factors, such as poverty and history of incarceration, represent significant and consistent correlates on HIV infection. HIV/AIDS stigma and homophobia are major barriers to effective HIV prevention and treatment, reducing access to testing, medical treatment, and uptake of novel biomedical HIV prevention technologies, such as pre/post-exposure HIV prophylaxis (PEP/PrEP), critical tools to interrupt HIV transmission in high risk populations and areas. Stigma and homophobia are often high in these areas and MSM experience them directly in their home neighborhoods and communities. Despite this, few community- level, anti-stigma and homophobia interventions have been developed and rigorously tested. Here we propose to conduct significant, formative research to develop and test a neighborhood space-based, anti-stigma and homophobia intervention. The novel components designed will be added to an established anti-stigma program, developed by an LGBTQ community organization, and delivered intensely to a single neighborhood over a 1-year period. To obtain a preliminary estimate of the efficacy of the intervention, we plan a quasi- experimental study, conducting 400 cross sectional street intercept surveys in two high HIV-prevalence neighborhoods, matched for sociodemographics and gay presence before and after the intervention (N=1600). Using linear change models with propensity score approaches to control for residual confounding between the intervention and control groups, we will assess changes in our outcomes, HIV/AIDS stigma and homophobia, as well as secondary outcomes in HIV knowledge and knowledge of and perceived access to HIV prevention services. Establishing preliminary efficacy of a community-level anti-stigma intervention addresses a major gap, potentially increasing access to HIV prevention technologies that can reduce HIV infection and lower community viral load in high HIV prevalence areas and populations.